Standing 111 centimetres tall and weighing 120 kilograms, the machine has the hospital's microbiologists smiling into their bacteria-smeared agar plates.

The machine, known as MALDI-TOF, has halved the time it takes to deliver bacteria results after patients have handed over physical samples, such as urine.

''It's a quantum step in the way we do microbiology,'' said the hospital's director of infectious diseases and microbiology, Peter Collignon.

Samples from as many as 96 patients can be tested in less than 40 minutes, and the machine spits out the first of the results within 30 seconds.

The old way of identifying a germ from a patient's sample took six hours or more and cost $8 a test because it used plastic containers that could not be reused.

''It's saving us $50,000 to $100,000 a year in consumables,'' said Professor Collignon.

It can still take days to grow and identify bacteria by looking at the cultures, but the overall time to receive a result has been cut from 48 hours to 24 hours.

The machine is being leased at present, but if it is bought at a cost of about $200,000, which might happen, it would easily pay for itself within a few years.

Microbiologists at the hospital still use their eyes to look at 120,000 tests a year to see which ones are positive.

About 15,000 to 20,000 positive tests a year will be put through MALDI-TOF to reveal more detailed information.

The number of tests the hospital's microbiologists do is increasing by 5 to 7 per cent a year.